- hydrology
- water-quality
Assimilative capacity is the headroom a receiving water has to absorb a pollutant load — or a withdrawal of flow — before a water-quality criterion would be exceeded. It is evaluated at a design low flow, conventionally the 7Q10, so the screen reflects the stream when it is least able to dilute.
In the water-balance analysis, the campus's consumptive cooling draw is subtracted from the live receiving-water flow and compared against the 7Q10: a negative balance means the consumptive loss erodes the dilution flow the permit record assumes, shrinking assimilative headroom. A negative figure is a screening flag — a lead to verify against the live gauge and the permit, not a verdict.